Closure for a container



Dec. 20, 1960 D. E. YOCHEM CLOSURE FOR A CONTAINER Filed April 1 1959INVENTOR. DONALD E. YOCHEM BY I v MAHONEY, MILLER & RAMBO ATTYS UnitedStates Patent C) CLOSURE FOR A CONTAINER Donald E. Yochem, 2859Northwest Blvd., Columbus, Ohio Filed Apr. 10, 1959, Ser. No. 805,452

1 Claim. (Cl. 215-43) My invention relates to a closure for a container.It has to do, more particularly, with a screw cap closure which ispreferably of a resilent plastic that fits on a container which is alsopreferably of plastic of a more rigid nature. The main object of thisinvention is to provide a screw cap which, when tightened on thethreaded neck of the container, will result in a leakproof closure ofthe container.

The accompanying drawing illustrates the preferred embodiment of myinvention and in this drawing:

Figure 1 is a vertical sectional view through a container andcooperating closure in which my invention is embodied showing theclosure in sealing position on the container.

Figure 2 is an enlarged vertical sectional view of the threaded upperportion or neck of the container showing the threads on the cap orclosure being initially engaged with the complemental threads on theneck of the container.

Figure 3 is a view similar to Figure 2 but showing the cap or closuretightened to sealing position on the neck of the container.

Figure 4 is an enlarged vertical sectional view through a portion of thecap or closure.

F.gure 5 is a horizontal sectional view taken along line 5-5 of Figure1.

With reference to the drawing, I have illustrated a closure or cap and areceptacle or container 11. The cap and container are both of annularcross-section and are both preferably formed of plastic. It is importantthat the cap 10 be of resilient plastic and that the container 11, or atleast its neck, be of a more rigid plastic. Both members are preferablyformed of thermoplastic resins and polyethylene has been used and foundmost suitable for the cap while polystyrene has been found most suitableand used for the container, although similar plastics may be used.

The container 11 is shown as being of cylindrical form but can takeother forms as long as its neck 12 is of circular cross-section. Theneck 12 on its outer surface is provided with deep angular threads 13extending from the upper extremity or lip 14 thereof inwardly a suitabledistance.

The cap 10 embodies a flat upper disk-like body 15 having a dependingflange or skirt 16 of annular form completely around its circumference.On the inner surface of this skirt 16 there is formed a deep angularthread 17 which is complemental to the thread 13 on the neck of thecontainer. This thread extends inwardly or upwardly from the lowerextremity of the skirt to a point adjacent the disk-like body 15 of thecap.

In order to obtain a leakproof unit when the cap 10 is tightened on theneck 12 of the container 11, I provide a very effective sealingarrangement of novel form. This sealing arrangement includes acontinuous annular convex sealing shoulder or surface 20 at the includedangle or internal corner of the junction of the disklike body 15 andskirt 16 of the cap 10 along with the annular angulated flange 21 spacedinwardly of the convex shoulder and providing an annular groove 22therebetween for receiving the lip 14 on the upper extremity of thecontainer 11. It will be noted that the sealingv shoulder 20 or surface20 is reversely curved so that it is convex rather than concave as isusually true of a radius in an included corner of molded plasticstructures. Thus, it may be termed a reversed radius surface. Thisreversed radius surface 20 is very important in the effective sealing ofthe cap 10 on the container 11.

The flange 21 cooperates with the reversed radius surface 20 in thesealing operation. This flange is relatively heavy compared to itsdownward extent and is provided with the outer angled or wedging surface25. The inner side of the flange may be vertical as indicated or angledif desired.

In the operation of this closure structure, the cap 10 is initiallypositioned on the neck 12 of the container 11 in the manner shown inFigure 2. In this position, the lip 14 of the container has not yetentered the downwardly opening annular groove 22 in the cap. It will benoted that because of the arrangement of the reversed radius surface 20and the upwardly and outwardly angled surface 25 of the flange 21, thegroove 22 has a diverging mouth and gradually narrows toward its topflat wall. It will also be noted that at its top flat wall the groove isof less width than the width of the lip 14 or upper extremity of theneck 12 of the container.

As indicated in Figure 3, as the cap 10 is tightened on the neck 12 ofthe container 11, the cooperating deep threads 17 and 13, respectively,thereof draw the cap firmly down on the container. As the lip 14 entersthe groove 22, the inner sharp margin 26 of the lip 14 squeezes againstthe angled surface 25 of the flange 21 and the outer sharp margin 27 ofthe lip 14 pinches against the reversed radius surface 20. Thus, theannular flange 21 inwardly supports the container neck 12 while thereversed radius annular surface 20 pinches and pushes on the outersurface of the neck of the container. The supporting flange 21 and thereversed radius surface 20 cooperate to maintain roundness of the openneck 12 of the container 11 and at the same time form an effective sealwhich is an hermetic seal. Since the reversed radius surface 20 and theangled flange surface 25 converge upwardly the seal is made moreeffective as the cap is tightened. However, the lip 14 will not engagethe flat top wall of the groove 22 even with the cap 10 in its tightenedposition, since, as previously indicated, the lip 14 or wall of thecontainer is of greater width than the groove at its top flat wall. Thiswill insure that the outer margin 27 of the lip 14 will always engagethe sealing reversed radius surface 20 and there will always be a smallspace 30 between the lip 14 and the top wall of the groove 22, as shownin Figure 3.

An important feature of this sealing arrangement is the sealing by meansof the outer margin 27 with the reversed radius or convex annularsurface 20. When polystyrene plastic or similar material is molded,sometimes there is flashing of plastic on the inner top side of acontainer. This is due to the core clearance which is necessary formolding the part. Such flashing produces small particles of plastic onthe inner or core side, then when a closure is placed, the flashing doesnot permit perfect contact with the top of the container and permitsleakage. However, during molding the outer surface of such containerscan be kept sharp and sufficiently free of plastic material that wouldinterfere with efficient sealing. Therefore, this sharp harder outeredge of the container will seal efliciently against the softer closure.Even though there may be some flashing on the inner margin 26 of the topof the container 11, the closure described herein will seal thecontainer. The space 30 3: between the cap and container can be occupiedby flashed plastic material on. the inner margin 26 of the container yetleakage will not occur because the container is sealed by the reversedradius 20 against the sharp outer margin 27 of the container.

It Will be apparent that I provide for an effective seal in a containerand closure combination where the cap is of relatively resilientmaterial and the container is of more rigid material so that its sharpupper edge will cut into the material of the cap. Although the containeris made of harder material, the neck wall is flexible because it is madeof minimum thickness for economy of material. However, the innersupporting flange will keep the container neck round during the sealingaction asthe outer margin of the top of the container bites into thereversed radius sealing surface.

According to the provisions of the patent statutes, the principles ofthis invention have been explained and have been illustrated anddescribed in what is new considered to represent the best embodiment.However, it isto be understood that, within the scope of the appendedclaim, the invention may be practiced otherwise than as specificallyillustrated and described.

Having thus described my invention, what I claim is:

In combination, a container of annular cross-section having an upperopen end with an exposed lip having inner and outer margins, said outermargin being sharp and continuous, said upper end of the container onits outer surface being provided with threads, a cap coopcrating withthe container and comprising a disc-like body with a depending skirt ofannular form, said skirthaving threads on its inner surface whichcooperate with the threads on the outer surface of the upper end of thecontainer so that the cap can be screwed onto the container andtightened into sealing position, said cap having a continuous reversedradius convex surface which is spaced axially above the upper extremityof the threads on said skirt in the included angle at the junction ofthe body and the skirt in sealing engagement with the continuous outersharp margin of the lip of the container when the cap is tightenedthereon, said body of the cap also having a depending continuous annularsupporting flange fitting within the upper end of the container forengaging the inner annular margin on said lip which is also continuous,said flange having an angled outer surface which cooperates with saidreversed radius convex surface to form a groove with upwardly convergingwalls for receiving said lip of the container and a top wall formed atthe inner surface of said body and which supports the upperend of thecontainer to hold said outer sharp margin of the lip of the container inengagement with said reversed radius convex surface, said lip of thecontainer being of greater width than the width of the groove at its topwall.

References Cited in the file of this patent UNITED STATES PATENTS

